Gas burner system



United States Patent [72] Inventor George McArthur,Jr.

Delaware, Ohio [21] Appl. No. 770,598 [22] Filed Oct. 25, 1968 [45] Patented Dec. 15,1970 I 73] Assignee Glenwood Range Company Taunton, Mass.

a corporation of Massachusetts.

[54] GAS BURNER SYSTEM 9 Claims, 8 Drawing Figs.

[52] U.S. Cl 126/39,

126/21, 431/284 [51] lnt.Cl F24c3/12, F24c 15/32 [50] Field of Search 126/39, 39C, 39E, 21, 21A, 19; 431/284 [56] References Cited UNITED STATES PATENTS 1,033,967 7/1912 Van Horn 431/284 2,193,055 3/1940 Brumbaugh 126/39E Primary Examiner-Charles J. Myhre Altorney.lerome R. Cox

ABSTRACT: A double input orifice fitting, for supplying gas to the oven burner ofa cooking range, is disclosed having two separately supplied, coaxial, output orifices. A single gas source supplies gas to each of the two orifices through two separate paths, each path being controlled by a separate valve. Each valve has on and off states. Fuel supply rate is con trolled by the orifice sizes so that selective actuation of the valves alternatively provides a high fuel supply rate and a low fuel supply rate. An enclosure is provided to contain the orifice fitting and has a bottom air intake opening communicating with the exterior of the range and a top exhaust opening. These provide a convection current of cooling air which sweeps and cools the orifice fitting.

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GEORGE M ARTH UR J R.

H6 5 Marja ATTORNEY GAS BURNER SYSTEM BACKGROUND OF THE INVENTION My invention relates to a gas burner system, and more particularly relates to a gas orifice fitting, a control therefor, and an enclosure for the cooling thereof, all for use in a gas cooking range. I

I have discovered that during the cleaning cycle of a gas self-cleaning oven it is desirable to deliver heat to the oven initially at a relatively low heat delivery rate. After the oven temperature has risen to a selected temperature, it is then desirable to deliver heat to the oven at a high delivery rate until a suitable cleaning temperature is reached. For example, reasons for this are explained in detail in my copending U.S. Pat. applications Serial No. 648,839, now U.S. Pat. No. 3,499,431, Ser. No. 680,368 now abandoned and Ser. No. 778,69I, now U.S. Pat. No. 3,504,660.

Two methods of obtaining such control have previously been disclosed by me. In one method, a single adjustable valve can be used to control the gas flow through an orifice and into the mixing bell of a gas burner. This valve is first adjusted for low fuel delivery rate and, after a selected temperature is reached, the valve is then adjusted to a high fuel delivery rate. In a second previously suggested method, two valves are used, each having two positions. Each valve can be turned off. One valve can be turned on but has a restriction so that, when on, fuel will be delivered at a low rate. The other valve either has no restriction or less restriction so that, when on, fuel is delivered at a high rate.

Both of these methods, however, utilize an orifice fitting with a single orifice. This has presented difficulties which the present invention overcomes.

The two desirable rates of fuel fiow'which are needed differ greatly. The initial flow rate is quite low for reasons explained in our said U.S. Pat. application Ser. No. 680,368, now abandoned, and raises the oven temperature to a selected temperature in the range of 250 F. to 450'F.' The later flow rate is quite high since it must be sufficient to raise the oven temperature above 950 F.

If a single orifice is used, it must be sufficiently large to permit the high flow rate. However, such a single orifice is too large for the low flow rate. Because of this, because the restriction which provides the low flow rate for a single orifice is located in the gas pipe ahead of the orifice, and because the gas pipe is large enough to accommodate the high flow rate, the result is produced that at the low rate gas flows through the large single orifice and into the mixing bell at an insufficient velocity. The insufficient velocity fails to produce sufficient aspiration of secondary air into the mixing bell. Furthermore, the low velocity flow becomes turbulent.

There is, therefore, a need for an orifice fitting and control which will provide two fuel flow rates but which will also permit proper functioning of the burner during either flow rate.

Further, because of the great quantity of heat necessary to clean an oven, and because in a gas ovenheat must be supplied by a relatively small device, l have discovered that the orifice fitting and the conduits leading thereto become too hot. This produces a heating and expansion of incoming fuel which remains at the supply line pressure. The result is fewer fuel molecules per minute being emitted from the orifice and therefore a reduction in the heat supply rate. There is therefore a need for a device which will sufficiently cool the orifice fitting without seriously cooling the temperature of the oven.

It is therefore an object of my invention to provide an improved orifice fitting and control therefor, and to provide improved means for cooling the fitting.

Another object of my invention is to provide an orifice fitting and control therefor which permit the selection of two substantially different fuel supply rates while maintaining a smooth flow of gas into the burner and maintaining sufficient aspiration of secondary air.

Another object of my invention is to providean orifice fitting in which proper gas velocity is maintained in the burner mixing bell.

Another object of my invention is to provide means for keeping the orifice fitting sufficiently cool to prevent excess gas expansion and to prevent the consequent reduction in heat supply rate.

Further objects and features of my invention will be apparent from the following specificationand claims when considered in connection with the accompanying drawings illustrating several embodiments of my invention.

SUMMARY OF THE INVENTION The foregoing and other objects may be attained in a gas burner system for supplying heat into the oven of a gas range at two selectable alternative heat supply rates; being of the type for use with a burner having outlet ports, a mixing bell, and having an inlet opening in the mixing bell; the burner system comprising: '(a) an orifice fitting for introducing fuel into the mixing bell through the inlet opening, the orifice fitting comprising: (1) a'body having a hollow portion therein, having a first outlet orifice communicating with said hollow and the exterior of the body, having a first inlet port communicating with the hollow and the exterior of the body and having a second inlet port; and (2) a conduit member positioned in the hollow, having a second outlet orifice, and communicating with the second inlet port; and (b) valve means comprising a supply pipe, at first pipe connected between the supply pipe and said first inlet port, a second pipe connected between the supply pipe and the second inlet port, a first valve in the first pipe, and a second valve in the second pipe; wherein the first valve controls the fuel supply to the first orifice and the second valve controls the fuel supply to the second orifice.

These and other objects are also attained with an enclosure containing the orifice fitting, the enclosure having an intake opening in its lower portion communicating with the exterior of the range for the intake of a convection current of ambient air, the enclosure further having an exhaust opening in its upper portion for the exhaust of the convection current from the enclosure; wherein the convection current of ambient air sweeps the orifice fitting and thereby cools it.

DESCRIPTION OF THE VIEWS FIG. 1 is a view in vertical section of an embodiment of the double input orifice fitting of my invention, taken substantially along the line l-1 of FIG. 3;

FIG. 2 is a view in sideelevation of the inner orifice conduit member of the orifice fitting shown in FIG. I, viewed at right angles to the direction of view in FIG. I, and illustrates the spacer enlargement provided on the inner orifice conduit;

FIG. 3 is a plan view of the orifice fitting shown in FIG. 1 with the hood or cap member of the orifice fitting removed;

FIG. 4 is a diagrammatic view of the burner orifice fitting cooling enclosure, and controls for an embodiment of my invention;

FIG. 5 is a view in vertical section of a portion of a cooking range and a gas burner system showing, mounted on the range, the orifice fitting shown in FIG. I and also showing an embodiment of the cooling enclosure cover'of our invention taken substantially along the line 5-5 of FIG. 6;

FIG. 6 is a front elevation view of the cooking range and burner system embodiment shown in FIG. 5;

FIG. 7 is a plan view of the cooking range and burner system of the embodiment shown in FIG. 5 with the orifice fitting and burner removed; and

FIG. 8 is a front elevation view of a gas cooking range illustrating the preferred position of the preferred embodiment of my invention.

In describing the preferred embodiment of the invention illustrated in the drawings, specific terminology will be resorted to for the sake of clarity. However, it is not intended to be limited to the specific terms so selected, and it is to be understood that each specific term includes all technical equivalents which operate in a similar manner to accomplish a similar purpose.

DETAILED DESCRIPTION In FIG. 8, I illustrate a gas range with its broiler door removed to show the position of a burner 10. A boxlike cover 12 is positioned partially below the burner, and partially in front thereof, and at the bottom, rear, and center of the broiler compartment. The orifice fitting (not shown in FIG. 8) is positioned within the cover 12. The burner 10 is generally L- shaped, having a portion behind the cover and another portion extending forward over the broiler compartment as illustrated diagrammatically in FIG. 4.

The details of my double input orifice fitting 20 are illustrated in FIGS. 1-3. The fitting is also shown in FIGS. Sand 6. The purpose of the double input orifice fitting 20 is to provide two separate paths for gas flow, each path terminating in an orifice located within the burner mixing bell 104 (See FIGS. 5 and 6). One path is terminated in a smaller orifice to provide a lower fuel delivery flow rate as further described below.

The fitting 20 comprises a cast brass body 22 to which a pair of mounting lugs 24 and 26 are attached. The body 22 has a removable portion which we refer to as a cap or hood 28 and which is threadedly engaged to the remainder of the body 22 by threads 30. This hood 28 has been removed in FIG. 3.

The body 22 is also provided with a first threaded inlet port 32 and a second threaded inlet port 34. The first inlet port 32 is in communication through a suitable passageway 36 with a hollow 38 formed in the interior of the body 22. A first outlet orifice 40 is drilled in the end of the hood 28 and communicates with the hollow 38 and the exterior of the hood. Thus a path for the high flow rate of fuel is provided through the first inlet port 32, the passageway 36, the hollow 38, and the first outlet orifice 40. I

A second path for the low flow rate of fuel begins at a second inlet port 34 provided in the body 22. An inner orifice conduit 42 is positioned in the hollow 38 and communicates with the second inlet port 34 by means of suitable passageways 44 and 46. The low flow rate path thus extends through the second inlet port 34, suitable passageways44 and 46, and the Y inner orifice conduit 42. This path terminates in a smaller second outlet orifice 48 provided in the end of the inner orifice conduit 42. The inner conduit 42 is engaged to the body 22 by threads 50 and is centrally spaced within the hollow 38 by means of a broadened portion of theconduit 42 forming a spacer 52.

It can be-seen that because both the first orifice 40 and the second orifice 48 are in close proximity and coaxial, my orifice fitting works very well in a single conventional burner. Gas flow during the low flow rate period will be controlled by the second smaller orifice 48. Although during the low flow rate gas will also flow through the first larger orifice 40, its velocity and flow will be unaffected thereby.

FIG. 4 illustrates, diagrammatically, the system for control of gas flow to the orifice fitting 20 and thence to the burner 10.

Fuel is supplied to the system from a single fuel supply pipe 60. A first pipe 62 is connected to the first inlet port 32 of the orifice fitting 20 and supplies fuel for the high fuel delivery rate. A second pipe 64 is connected to the second inlet port 34 and supplies fuel for the low fuel delivery. rate.

An electrically actuated double valve 66 is connected to the system. This double valve 66 comprises two separately actuatable valves having a common input connector 68 connected to the supply pipe 60. One outlet connector 70 is con nected to the first pipe 62, and the other outlet connector 72 is second valve in the second pipe 64 controlled at the terminals 76. The preferredvalves have only on and .ofi" states and thus are not continuously adjustable.

A voltage is applied to terminals 74 and 76 from power lines L1 and L2. The closing of a switch 77 applies the line voltage to terminals 76 and permits the flow of fuel through the orifice fitting 20 at a low rate. The closing of a switch 78 applies the line voltage to the terminals 74 and permits the flow of fuel at a high rate.

In FIGS. 5-7 I illustrate the cover used with my orifice fitting to keep it at a suitable temperature. Generally, the cover together with a portion of the oven liner provides an enclosure with an intakeopening in the bottom and an exhaust opening in the top. The bottom opening communicates with air below the range, and the top opening opens into the oven cavity. By suitable structure, a convection stream of ambient air sweeps the orifice fitting during its operation and thereby cools it.

Referring now in detail to FIGS. 5-7, the orifice fitting 20 is attached to the rear panel 80 of the broiler compartment by means of screws 82 and 83 inserted through its lugs 24 and 26. Gas is supplied to the orifice fitting by means of two conduits 62 and 64 connected to the two inletports of the orifice fitting. An intake opening 84 is provided in the bottom panel 86 of the broiler compartment. This intakeopening 84 communicates with the ambient air to permit the updraft of cooler ambient air. I

The cover 12 comprises a front panel 88, a pair of side panels 90 and 92, and a top panel 94 which extends only over a portion of the top of the cover. The remainder of the top provides the exhaust opening for the exhaust of the convection current from the enclosure. A baffle 96 is positioned vertically within the cover 12 and is provided with flanges 98 and 99 for attachment to the side panels 90 and 92 of the cover. This baffle provides an insulating layer of air current flowing between the baffle and the front panel 88 of the cover 12.

The burner 10, shown in phantom in FIG. 5, is mounted by suitable means including a yoke 102, so that its mixing bell 104 surrounds the orifice end of the hood 28 on the orifice fitting 20.

A pilot burner 108 is mounted to a strap llo which is fixed to the burner 10. The pilot burner 108 is, of course, provided with a suitable safety flame switch including a flame sensor OPERATION Referring primarily to FIG. 4, when the range is not in use, no voltage is applied to either the control terminals 74 or 76 so that both valves are shut off and no gas flows. For cooking use, suitable conventional circuitry controls and sensing devices are inserted (not shown) so that oven temperature is cycled around the desired cooking temperature. I prefer to cycle the oven by the periodic supplying of fuel through the pipe 62 and the large orifice 40.

To begin the cleaning cycle, a voltage is initially applied to the terminals 74 so that gas is supplied through the pipe 62 and the smaller orifice 48 and heat is supplied at a low rate. After the oven has warmed to a suitable temperature, such as 300 F. for example, a voltage is applied to terminals 76 so that gas is then supplied through the pipe 64 to the larger orifice 40 and heat is delivered into the oven at a high rate. I prefer that switch 78 be a temperature responsive switch which is made when oven temperature exceeds a selected value. It could, of course, be manually operated.

It would be possible, of course, to discontinue the flow of gas to the smaller orifice when flow to the larger orifice is begun. However, it is obvious that after fuel flow into the first inlet port 32 and the hollow 38 has begun, the presence or absence of fuel flow into the second inlet port 34 and out of the smaller orifice 48 will have no appreciable effect on the fuel flow rate from the larger orifice 40. This is so because the flow rate through the larger orifice 40 is dependent upon the pressure of the gas applied to the orifice. After fuel is permitted to flow into the hollow 38 through pipe 64, the pressure of gas at the orifice will be essentially the gas line pressure at the supply pipe 60. This pressure will not be affected by the presence or absence of gas flow through pipe 62 and the smaller orifice 48. Therefore, I prefer that during the high flow rate, both valves be open, because this permits control circuit simplification.

After the oven has been maintained at a suitable cleaning temperature for a sufficient length of time, both valves are shut off and the range is permitted to cool for subsequent use.

it is to be understood that while the detailed drawings and specific examples given describe preferred embodiments of my invention, they are for the purposes of illustration only, that the apparatus of the invention is not limited to the precise details and conditions disclosed, and that various changes may be made therein without departing from the spirit of the invention which is defined by the following claims.

lclaim:

l. A gas burner system for supplying heat into the oven of a gas cooking range at two selectable alternative heat supply rates; being of the type for use with a burner having outlet ports, a mixing bell and an inlet opening in the mixing bell; the burner system comprising:

a. an orifice fitting for introducing fuel into the mixing bell through the inlet opening, the orifice fitting comprising:

1. a body having a hollow portion therein, having a first outlet orifice communicating with said hollow and the exterior of the body, having a first inlet port communicating with the hollow and the exterior of the body and having a second inlet port; and

2. a conduit member positioned in the hollow having a second outlet orifice communicating with the second inlet port; and

b. valve means comprising a gas supply pipe, a first pipe connected between the supply pipe and said first inlet port a second pipe connected between the supply pipe and the second inlet port; a first valve in the first pipe, and

a second valve in the second pipe wherein the first valve controls only the fuel supply to the. first orifice and the second valve controls only the fuel'supply to the second orifice;

2. A burner system according to claim 1, wherein the second orifice is smaller than the first orifice and wherein each of said valves are positionable only at fully on and fully off states. Y

3. A burner according to claim 2, wherein the orifice fitting comprises:

a. a body having a bore and a counterbore which intersect to form a shoulder, having the first inlet port communicating with the counterbore and having the second inlet port communicating with the bore;

b. a conduit positioned in the counterbore having an outside diameter smaller than the counterbore diameter, having an inside diameter substantially equal to the inside diameter of the bore, having one end'in communication and sealed from the counterbore, and having said second orifice at its opposite end; and

c. a hood covering the open end of the counterbore and having said first orifice therein.

4. A burner system according to claim 2, wherein each of the counterbore, and having said second orifice at its opposite end; and a hood covering the open end of the counterbore and having said first orifice therein. A system according to claim 1, wherein the orifice fitting is mounted in a gas cooking range; and an enclosure is provided to contain the orifice fitting, the enclosure having an exhaust opening in its upper portion for the exhaust of a convection current from the enclosure, having a wall interposed between the outlet ports of the burner and the orifice fitting for. blocking substantially all heat transfer by radiation from the burner flame to said orifice fitting and said mixing bell, and having an intake opening in its lower portion communicating with the exterior of the range for the intake of said convection current wherein a convection current of cooling air sweeps the orifice fitting and thereby cools it.

7. A device according to claim 6, wherein said enclosure comprises:

a. a portion of an interior vertical panel of said range;

b. an adjacent portion of a horizontal interior panel of said oven provided with said intake opening therein; and

c. a cover comprising 1. a vertical front panel spaced from said vertical interior panel and abutting said horizontal panel; and

2. a pair of vertical side panels extending from the edges of said front panel to said vertical interior panel.

8. In a gas cooking range of the type having an oven, a burner, and an orifice fitting for supplying gas to the burner, the improvement comprising, an enclosure containing the orifice fitting, the enclosure having an intake opening in its lower portion communicating with the exterior of the range for the intake of a convection current of cooling air, the enclosure having a wall interposed between the outlet ports of the burner and said orifice fitting for blocking heat transfer by radiation from the burner flame to said orifice fitting, the enclosure further having an exhaust opening in its upper portion for the exhaust of said convection current from the enclosure, wherein the convection current of air sweeps the orifice fitting and thereby cools it.

9. A device according to claim 8, wherein said enclosure comprises:

a. a portion of an interior vertical panel of said range;

b. an adjacent portion of a horizontal interior panel of said oven provided with said intake opening therein; and

c. a cover comprising:

1. a vertical front panel spaced from said vertical interior panel and abutting said horizontal panel; and

2. a pair of vertical side panels extending from the edges of said front panel to said vertical interior panel. 

